What Causes A Pond To Foam?Published: Tue, 20 Oct 2009
What causes a pond to foam?
During the summer, bubbly foam forms on the surface of many ponds, particularly around waterfalls, venturi’s or where the bubbles from an air pump break the surface. Although the foam does not exclusively just form during the summer, the warmer temperatures, fish spawning and the higher protein diet that pond keepers feed to their fish during the summer are the usual triggers for foam to form.
The main culprit behind the foam forming is protein that is broken down and oxidised in the water. As mentioned in the previous article “How does my biological filter work”, protein can come from rotting fish, plants or food as well as from fish respiration and excretion. When this protein is oxidised it turns into the potentially deadly compound known as ammonia (NH3).
Proteins are hydrophobic, meaning they are repelled by water and attracted to air. The dissolved proteins quickly attach to the air bubbles and rise to the surface forming an unsightly foam. This process is known as foam fractionation and is used in protein skimmers to remove protein from the water before it is oxidised into ammonia.
What to do should your pond develop foam?
The first port of call is to discover what is causing the foam as this helps to prevent this problem from reoccurring. Next the water within the pond should be tested for ammonia (NH3) and nitrite (NO2) with an accurate tablet or liquid test kit such as the API Master Pond Test Kit which many of the Ings Lane staff use on their home ponds and aquariums. Testing for ammonia and nitrite is wise in case these compounds are at a level dangerous to your livestock. The foam can then be controlled by checking for excessive decaying matter as mentioned previously (silt and sludge does not cause foam but should be kept to a minimum), reducing food and by using an anti-foaming treatment such as NT Labs – Anti-Foam
Article by Jackson Sage.
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